There are many instances where in a production of material it is necessary to tie a knot. This is usually done by hand if the number is small and is a very time consuming operation; while this is usually done by automatic knot tying device if the number is large. In one particular instance, the production of collagen casings for use in the food industries such as sausage making, it is necessary to tie a single knot in the end of the casing so that when the casing is filled the filling material will not burst out of the end.
Collagen casings are produced in very long lengths which are shirred into a compact “stick”, i.e. shirred casing stick, and one end is normally sealed. It is possible to seal the end by a lot of methods, but a knot is the most satisfactory, particularly when dealing with sausages, where the filling pressure is very high or the filling material is high in fluidity.
However, the existing knot tying device has the defects of complicated structure, complex actions, low speed, high cost and inconvenient operation.